Modelling GWR Slip Coach operation -

[MarkAustin]

I used the term 'driven' as it took skill for the guard to manage the braking (and the limited brake cylinder volume) and stop the coach in the platform. It certainly wasn't a case of just unhook and then wind on the brake.

 

With gradients you risk roll-back, which certainly isn't prototypical. In DC I'd be inclined to add drag to the axles and experiment until the correct combination of train speed, detaching point, and drag was found.

 

Adrian

 

They didn't just rely on the vacuum cylinder: they had extra cylinders to give more braking power. This photgraphs shows them under the coach http://www.scienceandsociety.co.uk/results.asp?image=10306871&itemw=4&itemf=0001&itemstep=1&itemx=4

[Adrian Wintle]

They didn't just rely on the vacuum cylinder: they had extra cylinders to give more braking power. This photgraphs shows them under the coach http://www.scienceandsociety.co.uk/results.asp?image=10306871&itemw=4&itemf=0001&itemstep=1&itemx=4

Or they had them along the roof on clerestories, yes. They still only had a limited amount of vacuum to play with. And it doesn't give more braking power, just the same braking power for longer, allowing the brake to be modulated.

 

Adrian

[The Stationmaster]

Or they had them along the roof on clerestories, yes. They still only had a limited amount of vacuum to play with. And it doesn't give more braking power, just the same braking power for longer, allowing the brake to be modulated.

 

Adrian

Sort of - yes they had a large vacuum reservoir capacity but the purpose of it was to allow the brake to be kept off until it needed to be applied and to give some measure of control by allowing the brake to be blown back off (to some extent) if the initial application was too fierce or misjudged.

[Adrian Wintle]

Sort of - yes they had a large vacuum reservoir capacity but the purpose of it was to allow the brake to be kept off until it needed to be applied and to give some measure of control by allowing the brake to be blown back off (to some extent) if the initial application was too fierce or misjudged.

I presumed that the extra tanks were there to provide a vacuum reservoir that allowed the coach brake to be pulled off a limited number of times (or to a limited extent) i.e. the extra reservoirs were a replacement for the vacuum line from the loco rather than being an oversized vacuum cylinder. Of course the vacuum would decrease as you used it to pull the brakes back off, but it was effectively a large vacuum 'capacitor'. 

 

Adrian

[Ozexpatriate]

Per the discussion on the wishlist poll here ...

.... I'd still like to see the option to vote for a pre-1938 slip coach.

Oz: I ... will also add the Pre-1938 Slip Coach if you can give me a diagram number or such like.

It is time for me to invest in some decent GWR reference material. If anyone has any recomendations along the lines of something I could acquire online, (although airmail on heavy large format books can be a bit extreme) please let me know.

 

In the meantime, if anyone has suggestions for slip coach diagrams that would match the illustrations on this page, that I could pass on to Brian MacDermott please let me know.

Edited April 1, 2013 by Ozexpatriate

[Adrian Wintle]

That could be an F14 Toplight Single Slip. Certainly it is a toplight-based slip coach. I have Hammond sides for one somewhere.

 

For references, the 4 volumes of Russell, the Harris book, and the Wild Swan Official Drawings book - see http://www.gwr.org.uk/nolitt.html

If you want one book with an overview and the lot lists get Harris, otherwise Russell Vol. 2 is probably the best single volume (photos and diagrams post ~1900).

 

Adrian

Edited April 1, 2013 by Adrian Wintle

[Ozexpatriate]

Wow! Adrian, that was quick. Thank you.

 

(Yes, I am very partial to toplights.)

[Adrian Wintle]

Wow! Adrian, that was quick. Thank you.

 

(Yes, I am very partial to toplights.)

 

Your reply was too quick - I edited my response to add a list of references...

[Ozexpatriate]

Thank you - googling the F14 (in parallel) I just found that reference to the Wild Swan Official Drawings book on gwr.org.

Edited April 1, 2013 by Ozexpatriate

[Adrian Wintle]

Thank you - googling the F14 (in parallel) I just found that reference to the Wild Swan Official Drawings book on gwr.org.

 

The Wild Swan book would be the cheapest (both to buy and to ship) since it is a fairly thin softback book. It has limited coverage (only the coaches on the list), but is very good for those.

 

The Russell volumes in particular are heavy books.

 

There appear to be some copies of the various books available from US sources, some even at not totally unreasonable prices (I have no knowledge of the sellers)

http://www.amazon.com/gp/offer-listing/0715355023/ref=dp_olp_0?ie=UTF8&condition=all

http://www.amazon.com/gp/offer-listing/0902888048/ref=dp_olp_0?ie=UTF8&condition=all

 

Adrian

[BMacdermott]

Hello Oz

 

I have just caught up with your posting No.30. Could you email that link to me at: ThePollTeam@gmail.com? Author John Lewis is a member of The Poll Team, and I'm sure he will be able to help you.

 

Brian Macdermott

[Ozexpatriate]

I have just caught up with your posting No.30. Could you email that link to me at: ThePollTeam@gmail.com?

Done.

 

Thank you Brian.

[Siberian Snooper]

If I were you I'd check first that the books are available where you are. A friend of mine wanted a book for her sisters Christmas present and was going to buy it here in Blighty and send it to New Zealand u, until I pointed out that it might be available there. A quick check on the interweb proved fruitful and saved a shed load in shipping charges.#

 

SS

[Adrian Wintle]

If I were you I'd check first that the books are available where you are.

 

Hence the links to sources in the US in post #35...

[t-b-g]

I don't have the inclination to do the maths but for a slip carriage to stop from, say 50 or 60 mph in a platform it is going to have to be released some way before the platform, unless the passengers are going to be flung about by severe braking.

 

Peter Denny had a slip carriage on Buckingham, but with inside bearings and low speeds the uncoupler was only just at the end of the platforms and the slow down and stop was a bit fierce. That used three link couplings with an "on board" uncoupling hook worked via a treadle under the carriage, activated by a tiny ramp between the tracks.

 

Unless anybody has a huge layout, the actual uncoupling would very likely be off scene and perhaps a motorised carriage following behind the train is an easy option and does away with any coupling worries. It is very tricky to get a carriage to move realistically without it being powered, as you would struggle to replicate the brake being applied.

 

Tony

[Coach bogie]

That could be an F14 Toplight Single Slip. Certainly it is a toplight-based slip coach. I have Hammond sides for one somewhere.

 

For references, the 4 volumes of Russell, the Harris book, and the Wild Swan Official Drawings book - see http://www.gwr.org.uk/nolitt.html

If you want one book with an overview and the lot lists get Harris, otherwise Russell Vol. 2 is probably the best single volume (photos and diagrams post ~1900).

 

Adrian

 I agree with Adrian. I think it is the F14, and it matches my Hammond sided example. The lack of van section identifies it as an F14 rather than a F20.

 

My 4mm F14 is made from Hammond sides with PC slip/corridor ends and parts. The similar F20 can be made from a Blacksmith E95 with a slip end etch at one end. The F20 is being discussed on the toplight thread.

 

Mike Wiltshire

[Ozexpatriate]

... perhaps a motorised carriage following behind the train is an easy option and does away with any coupling worries. It is very tricky to get a carriage to move realistically without it being powered, as you would struggle to replicate the brake being applied.

Yes, this is the essence of what I was looking for in the OP - what do people think would work best.

[London cambrian]

Just caught up with this one, a topic i've always been fascinated with!

The best example of working slip coaches i have seen ws on a gauge 1 layout at a model engineering show. A GW Clerestory slip was released from the back of the train, hauled by a GW City class, did a lap and a half of the circuit and rolled to a stop pretty in the station road, though i dont know if he had any brakes in it.

 

Bu this was the genesis of my own project, i'm now aiming to build a working slip coach in 5 inch gauge (approx 12th scale). I'm almost at the stage of cutting metal and wood, this summer perhaps. its involved a lot of design work to take the GW F15 Double ended Toplight slipinto CAD, and include in the design a scale slip coupling, controlled by radio control, as well as working scale brake gear, and if needed, for emergency an ideler motor just to keep it going more than anything else, as it will roll to a stop of its own accord!

 

Like the above i have a soft spot for the Toplight design! I chose the F15 design,because its double ended and i wouldnt have to put it on the turntable too often! Too my knowledge all the designs are available (though the russell ones have been redrawn, making my life difficult) this book i found the most useful http://www.transportdiversions.com/publicationshow.asp?pubid=2659

It contains by far the best plans of the single ended F14 slip coaches, being the works drawings.

 

i borrowed the books from the local libraries, and scanned in the pages i needed, which i may be willing to share privately of course if people are in need of them.

 

All the best, i look forward to seeing any results of this conversation!

 

Mark

[Ozexpatriate]

... and include in the design a scale slip coupling, controlled by radio control, as well as working scale brake gear, and if needed, for emergency an ideler motor just to keep it going more than anything else, as it will roll to a stop of its own accord!

Mark,

 

thanks for the reference.

 

Perhaps a nice heavy flywheel would be the perfect thing instead of an idler motor for your 5" gauge model. I'm guessing the mechanics would be simpler (some visible gearing/contact wheel or belt is necessary either way) and it would respond to the brakes quite prototypically.

 

Does the F15 diagram have an underbody mounted generator? If this were modelled with a working belt, a lead weight in the generator housing might be all the extra rotating intertia you need and look perfectly prototypical.

[London cambrian]

Hiya Oz

 

I have thought along these lines, but decided because of the weight of the wheels already (all aluminium or steel wheels) the effect of a flywheel would be fairly negligible on the overall motio of the coach, even on roller bearings (which is will be)

 

I hadnt thought of the generator, and i love the idea,but i rather fear that even in our spacious scale, the corners can get too tight , and i'd spend my life remounting it!

 

The idea of the idler (a motor with a rubber tyre running on a disc on the xle, or even the wheel itself) is a get out of doge, to keep it going, in thei get it wrong with either braking, or release point. Its an insurance policy, because at the rallies we run at, there's everything is timetabled, and there are station and yard pilots who could come an collect the coach when necessary. I have no doubt it will run far enough, which some smaller models may suffer from, its the worry of human error than makes me think about putting an idler in. luckily we have a lot of space under it and already a raio channel going to it i don't for see it as a problem. I only wish we were able to use the dynamo belt for it! Though to tell you the truth i'm not sure it carried one, though you'd presume it would?

 

Cheers

 

Mark

[Neal Ball]

Ok so who is now going into production / commission a 00 GWR working slip coach??????

[London cambrian]

By saying working how would you mean? A DCC operated slip coupling? DCC brakes/motor?

[Ozexpatriate]

GWR Slip Coach fans,

 

Brain Macdermott contacted John Lewis on the poll team regarding slip coaches. and a week or so ago replied to me with the following suggestions for slip coaches from John:

F14 toplight - gangway connector at one end
F15 toplight*
F16 toplight*
F20 steel panelled design - gangway connector at one end
F21 (70') double-ended slip

* having different internal corridor arrangements. John suggests that the slip coach illustrated here is an F16.

 

I would like to make a recomendation to Brian for the 2014 poll for a GWR slip that operated Ca ~1930. In the spirit of the poll, I'd like to suggest one (rather than all of them) and am leaning to one of the toplights.

 

Do any of you have any suggestions?

[69843]

A double slip could be interesting to get working both ways.

 

Now, I remember copying an article out of Railway Modeller a while back on how they did an operating coupling for a slipcoach. I think they used a small RC car motor to raise the 'hook' bit of the tension lock (suitibly altered with filed flat hook), and let it coast into the platform. I'll see if I can find the article soon.

[Ozexpatriate]

BUMP

 

I was remiss in not making a recommendation to Brian Macdermott on a diagram for a slip coach to be included in the 2014 MREmag & RMweb wishlist poll and need to do so soon.

 

F13 (70') concertina double-ended slip (also CSP / Haye kit)

F14 toplight - gangway connector at one end
F15 toplight*
F16 toplight* (apparently there was once a Mallard / CooperCraft kit)
F20 steel panelled design - gangway connector at one end
F21 (70') double-ended slip

* having different internal corridor arrangements. John Lewis suggests that the slip coach illustrated here is an F16.

 

Any takers?

 

Any better descriptions than those above?